level_up now works with Python>=2.7

Specificially, python just needs to be able to run

    >>> from __future__ import print_function

and everything should work fine. The tkinter module is capitalized
differently in Pythons 2 and 3, but a try/except block deals with that.
Merge branch 'master' of upstream branch

Conflicts:
	Dependencies.md
Removed explicit python3 requirement from level_up

I just changed the shebang line of the actual script. The OS should use
whatever it thinks is the standard python. Everything should work fine
whether that's py3k (i.e., on Arch Linux) or 2.7.x (everywhere else).
Merge pull request #40 from ahammel/master

level_up works with Python>=2.7

I've tested the new version with Pythons 2.7.4 and 3.3.1. All that's changed is some import magic, so I'm pretty confident that I haven't broken anything on other systems.